%------------------------------------------------------------------------
% Program that used to give wrong results.
%
% Model T = {r}, F = {p,q}, U = {}.
%------------------------------------------------------------------------

:- table p/0, q/0, r/0.

p :- tnot(q), p.
q :- tnot(q), p.
r :- tnot(p).
q :- tnot(r).

%------------------------------------------------------------------------

test :- q, fail.
test :- ( p ->	( tnot(p) -> writeln('p is undefined')
		; writeln('p is true') )
	; writeln('p is false (OK)') ),
        ( q ->  ( tnot(q) -> writeln('q is undefined')
		; writeln('q is true') )
	; writeln('q is false (OK)') ),
	( r ->  ( tnot(r) -> writeln('r  is undefined')
		; writeln('r is true (OK)') )
	; writeln('r  is false') ).
